The high thermal conductivity of graphene prevents ZnO nanorod-graphene interface from degradation

Abstract

The electrical and thermal properties of the junction between individual ZnO nanorods and conductive electrodes are investigated. It is demonstrated that a stable ohmic contact can be prepared between ZnO nanorods and graphene by eliminating contamination on the graphene surface by local Joule heating. Moreover, it is shown that, for conventional metal electrodes, such as copper, Joule self-heating forms hot spots and subsequently causes thermal damage to the ZnO nanorod near the interface. This issue can be eliminated in graphene contacts because of their excellent thermal conductivity. The experimental results are validated by the numerical modeling of heat dissipation near the ZnO/graphene interface using COMSOL Multiphysics software. To characterize the interface between individual nanorods and graphene, a novel technique was developed using a nanomanipulator in the chamber of the scanning electron microscope. In contrast to conventional approaches, the method eliminates the use of extensive processing chemistry and allows observation of morphological changes in situ when performing electrical characterization.